Haumea: Technique and Rationale

byPaul GilsteronJuly 15, 2009

Yesterday’s look at a fast orbiter mission to Haumea raises useful questions. The mission, developed conceptually by Thales Alenia Space and presented at Aosta by Joel Poncy, is particularly demanding because this outer system object has no atmosphere. You can make the case for a Neptune orbiter with associated study of Triton, as several readers have already done, but if you want to orbit Haumea, no aerobraking is possible to ease orbital insertion.

The Haumea mission, in other words, deliberately pushes the state of the art in both propulsion and power generation. Poncy noted in his talk at the Hotel Europe that his team had adapted an in-house software model to optimize the propulsion possibilities. The team considered only electric or magneto-plasma technologies (for the latter, think VASIMR — Variable Specific Impulse Magnetoplasma Rocket). They assume a direct trajectory to Haumea with arrival around 2035, when the object is at 49 AU, and they weigh the benefits of a gravity assist by Jupiter to help shorten the journey.

Image: The orbits of Hi`iaka (outer satellite) and Namaka (inner satellite). Namaka’s orbit is nearly edge on as viewed from Earth. Every nine days Namaka passes directly in front of or behind Haumea as seen from Earth. Credit: University of Hawaii/D. Ragozzine.

Taking the hardware to its limits, Poncy and colleagues come up with what looks to be a feasible mission concept, one with a specific impulse of 10000 seconds, a launch mass of 3000 kilograms and a flight time of about 21 years. Says Poncy:

This set of parameters corresponds to what should be achievable in a near future, provided that VASIMR and beta-voltaic technologies are implemented into respectively propulsion and power units by adapting their design and operating point to this class of spacecraft.

A lot is in play here. For one thing, VASIMR is more promise than reality at these levels — will it perform as advertised? For another, Poncy himself notes the problem with generating the power needed to fly this mission. Here’s his thought on that:

…the current technologies would fall short of the needs. The beta-voltaic technology looks promising, as values up to 24W/kg might be within reach in the coming years providing that the packaging design and the battery assembly are adapted to the production of several kW… If we want to go beneath 20 years [flight time], then the industry and the agencies will have either to undertake even more ambitious developments for the power generation, so as to reach about 50W/kg in terms of power density, or find new disruptive technologies.

Yesterday I talked about the scientific value of a Haumea mission, but the second motivation for going to this distant object is to use the mission as a technology driver. Poncy was exactly right when he told the audience at Aosta that if we’re going to get serious about Solar System colonization and, ultimately, interstellar travel, we need to develop the near-term technology to reach and orbit objects in the outer system with less than ten to twenty years of cruise. And don’t forget, these trans-Neptunian objects (TNOs) are rich in volatiles and organics, interesting places for future robotic or even human outposts.

Image: Haumea and its moons. Credit: NASA GSFC.

Moreover, we’re intent on exploring the moons of the gas giants, which is going to demand developing next generations orbiters, landers and deep-drilling capabilities. A fast journey to an object like Haumea thus becomes a way to extend our science to planetary objects within 100 AU that can at the same time increase our capabilities for reaching Jupiter or Saturn space with the kind of heavy payloads we want to see in operation there. Poncy sees Haumea as a targeting goal for developing the next tools we need as we expand our studies of closer worlds like Europa and Titan.

The paper is Poncy et al., “A Preliminary Assessment of an Orbiter in the Haumean System: How Quickly Can a Planetary Orbiter Reach Such a Distant Target?” It’s in Proceedings of the Sixth IAA Symposium on Realistic Near-Term Advanced Scientific Space Missions, and should therefore pop up in the near future in Acta Astronautica.

Comments on this entry are closed.

James M. EssigJuly 15, 2009, 14:47

Hi Paul;

Perhaps short half-lived radionucleids as waste left over from spend nuclear reactor fuel can provide the above 50 W/kg. For radionucleids with a half life of anywhere from 30 years to 100 years enclosed in very effecient radio-thermal-electric generators Isp values of as much as 100,000 seconds might be obtainable.

A fission reactor that would burn its waste to reduce it to a significantly lower potential energy state might provide for a greater Isp than single reaction decay chains for nuclear fission.

With the announcement that the Lunar soil has Uranium within it, perhaps massive utilization of nuclear fission can get us to the stars.

A VASIMAR rocket or similar rocket can in theory utilize an extremely relativistic plasma or ion beam for improved rest mass specific specific impulse which can in theory approach infinity to the extent that the kinetic energy of the particle exhaust can approach infinity. In practicality, a machine that would exhaust 10 TeV protons would likely be the size of the Large Hadron Collider with today’s technology.

Pu-238 – one of those leftovers from reactors Jim mentioned – puts out about 557 W/kg of heat, but the problem is not with the heat-source, but converting the heat into useful energy. The beta-voltaics Paul mentions are sort-of ‘solar panels’ for converting radiation directly into electricity, though their efficiency is pretty low. Their advantage – as well as using Pu-238 heat instead of a fission reactor – is the lack of moving parts. A good thing when running a system for decades at a time.

Of course if we had high-thrust & high exhaust velocity the engines wouldn’t need to fire for two decades. But we’re currently severely stretching existing technology to get 0.5 kW/kg out of a space reactor, let alone MW/kg needed for high-speed probes.

As for LINAC (linear accelerator) propulsion, it suffers from the same liability as ion-drives – the power-source inefficiency makes it practically useless for interstellar travel. The only practical LINAC/ion-drive I’ve seen for interstellar travel is the kind that gets power via laser beam from a fixed source. According to detailed analysis by Geoff Landis that design is more efficient than laser-propulsion alone for speeds below ~0.2 c. A laser-powered RAIR is more efficient than either – even more so when accelerating into a beam from the target system because the laser-light is blue-shifted to higher energies.

Maybe we should stop thinking about orbiters to worlds like that for right
now and go straight to impactors, both survivable and the kind that gather
and transmit data right up until their sudden encounter with said celestial
body.

Since an orbiter probe would need so much fuel to brake and get in the
right pattern to circle said world, etc., why don’t we wait a bit for the
technology to perform such manuevers to catch up and start with a
fast probe that would be deliberately stopped at Haumea and other
such KBO worlds. I am assuming the technology to zip a probe out
there without all the bells and whistles of orbiting is available now
or will be very soon.

In addition to the obvious benefit of just being there with a robot probe,
we could at least learn as much as Deep Impact did at Temple 1 if we go
with a non-suvivable impactor. Of course if we have something like the
Deep Space 2 very hard landers sent to Mars in 1999 (but ones that
actually, you know, survive the hard landing), then we will have a very
valuable if stationary automated station on said world to relay all kinds
of data.

I am assuming here that if we don’t have the means to place an orbiter
around a KBO yet that it will be just as or nearly as difficult to soft land
a probe on such a world, thus the idea of a vessel that can survive a very
hard landing to relay back at least some data from the surface.

So, is such an idea feasible with what we have now? Would such a mission
be worth it, or do we just wait for the orbiter versions?

jim,adam,what a difference a day makes!! yesterday just going back to the moon was the question,today,lol, we forsee MINING the moon! eerrr ahhh we should kinda sorta get back there first! however let me say this everybody.you know that quick vote you get when you first sign on? well i just saw one.”should we go back to the moon”? i said yes.i was with the 57%. – 43% said no.in my opinion a sort of high figure.incredible. on another part of this same site even i ventured to say that just maybe we could do more exciting things before we went back.but should we go back? yes.we have to.imho the moon and mars will be the stepping off places for the rest of the solar system – followed by the kuiper belt,oort cloud and the rest of the galaxy! nobody should think that strange after all our main business here IS starships! very respectfully to one and all your friend george

As useful as the Moon might be IMO the first mission should be to an NEO for a bit of resource assaying. The NEOs are more useful than the Moon. Tanked up on NEO water a nuclear thermal rocket can each Mars, the Main Belt and Jupiter’s moons very easily, for less reactor power than cracking the water into H2/O2 then just using the H2 as reaction mass.

Not only is the Moon short of H2O, but it’s also short of C/H/N in general – whereas an NEO of the right type is full of water and kerogen. Of course we’d have to learn how to extract the stuff in a milli-gee environment, but that’s a useful cluster of techniques when building in-space anyway.

Unless we invent a Tiplerian Total-Annihilation Neutrino drive, then all our starships will be built in-space.

Cosmic microwave background radiation peaks at about 0.0019 meters or 1.9 x 10 EXP -3 meters. Visible light has a wavelength of about 380 nanometers to about 750 nanometers or about 3.8 x 10 EXP – 7 meters to 7.5 x 10 EXP – 7 meters. For a craft with a relativistic gamma factor of about (1.9 x 10 EXP – 3 meters)/(3.8 x 10 EXP – 7 meters) = 5,000, the wavelength of the cosmic microwave background radiation impinging on the craft from the front of the craft would be roughly equal to the visible light spectrum, or black body radiation of roughly the visible light spectrum. Provided photovoltaic cells could be mounted on the front of the space craft, that could operate at a black body radiation temperature of roughly a few thousand Kelvin, a very tall order indeed considering that current concentrated light photovoltaics of state of the art research are much more limited in their refractive properties, a space craft upon reaching a gamma factor of 5,000 could power enourmously powerful ion, electron, or photon rockets, or electro-hydrodynamic–plasma-drive, magneto-hydrodynamic-plasma- drive, electro-magneto-hydrodynamic-plasma drive craft and the like.

A more reasonable gamma factor for the craft before onset of Photovoltaic energy extraction may be in the 1,000 range.

Now imagine if by chance steam turbine systems on steriods could be developed wherein the CMBR energy, blueshifted by a factor of z = 5,000 would be absorbed by extremely absorptive surfaces in front of the space craft through which high pressure steam conduits run such that the super heated steam would then drive turbo-electric generators which in turn would provide very high levels of electrical power to electrical propulsion systems such as ion, electron, or photon rockets, or electro-hydrodynamic–plasma-drive, magneto-hydrodynamic-plasma- drive, electro-magneto-hydrodynamic-plasma drive craft and the like.

The thermal mass in front of the craft that absorbes the incident CMBR energy so blue-shifted would likely be composed of some forms of highly absorbtive carbon that has a very high thermal conductivity such as diamond, or the more refractive of metallic elements and compounds such as can withstand temperatures on the order of 3,000 K or even higher before reaching their melting point.

Some possible materials for such applocations might be carbon graphite fiber cloth, diamond fiber cloth, carbon nanotube based bulk materials, carbon graphene materials, bulk materials formed from the very robust molecules of carbon fullerines such as carbon buckyballs and the like materials.

The ability to remove heat very quickly from the frontal thermal masses of the craft is a requirement for such a system based on ordinary molecularly bonded matter. However, in addition to using water steam as a means to extract heat from the very hot thermal mass, perhaps liquid sodium conduit based heat extraction could work or the use of another high heat conductivity molten liquid could be made. Note that during the Cold War, the Soviet Navy experimented with liquid metal cooled reactors while the U.S. Navy largely did its most extreme research with steam powered systems which are used today throughout the entire U.S. Navy.

Now in theory, materials that conduct phonons or thermal vibrations in solid materials from cold to hot can exist. Although for the purposes of this article, we are considering the removal of excess heat only, and such materials may be able to conduct thermal atomic vibrations much more effectively than ordinary high heat conductivity refractive materials.

thank you very very much guys for your opinions! yes near earth objects might indeed be very useful to visit.no arguement there.might be the perfect “practice” for alot of things! wish we could just get some kind of a program together to know what the heck it is we are going to try to do! thanks again,your friend george

IMHO a mission to Haumea – or anywhere between the Oort and the EKB – might be a good chance to employ beamed propulsion concepts. The desorption microwave sail developed by the Benfords is a good near-term technology option.

A dark red area discovered on dwarf planet Haumea appears to be richer in minerals and organic compounds than the surrounding icy surface. Since Haumea is so small and far away, it shows up in telescopes as just a point of light, but the spot was discovered by measuring changes in brightness as it rotates. Small but persistent differences indicate that the dark spot is slightly redder in visible light and slightly bluer at infrared wavelengths.

The spot could be from a recent impact, so scientists aren’t sure if the materials come from Haumea or the impactor. The dwarf planet is thought to be a rocky body covered in ice.

“Our very first measurements of Haumea told us there was a spot on the surface” said Dr. Pedro Lacerda, from Queen?s University in Belfast. “The two brightness maxima and the two minima of the light curve are not exactly equal, as would be expected from a uniform surface. This indicates the presence of a dark spot on the otherwise bright surface. But Haumea’s light curve has told us more and it was only when we got the infrared data that were we able to begin to understand what the spot might be.”

Abstract: A second large programme (LP) for the physical studies of TNOs and Centaurs, started at ESO Cerro Paranal on October 2006 to obtain high-quality data, has recently been concluded.

In this paper we present the spectra of these pristine bodies obtained in the visible range during the last two semesters of the LP. We investigate the spectral behaviour of the TNOs and Centaurs observed, and we analyse the spectral slopes distribution of the full data set coming from this LP and from the literature.

We computed the spectral slope for each observed object, and searched for possible weak absorption features. A statistical analysis was performed on a total sample of 73 TNOs and Centaurs to look for possible correlations between dynamical classes, orbital parameters, and spectral gradient.

We obtained new spectra for 28 bodies, 15 of which were observed for the first time. All the new presented spectra are featureless, including 2003 AZ84, for which a faint and broad absorption band possibly attributed to hydrated silicates on its surface has been reported. The data confirm a wide variety of spectral behaviours, with neutral–grey to very red gradients. An analysis of the spectral slopes available from this LP and in the literature for a total sample of 73 Centaurs and TNOs shows that there is a lack of very red objects in the classical population.

We present the results of the statistical analysis of the spectral slope distribution versus orbital parameters. In particular, we confirm a strong anticorrelation between spectral slope and orbital inclination for the classical population. A strong correlation is also found between the spectral slope and orbital eccentricity for resonant TNOs, with objects having higher spectral slope values with increasing eccentricity.

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For the last twelve years, this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image: Marco Lorenzi).

If you'd like to submit a comment for possible publication on Centauri Dreams, I will be glad to consider it. The primary criterion is that comments contribute meaningfully to the debate. Among other criteria for selection: Comments must be on topic, directly related to the post in question, must use appropriate language, and must not be abusive to others. Civility counts. In addition, a valid email address is required for a comment to be considered. Centauri Dreams is emphatically not a soapbox for political or religious views submitted by individuals or organizations. A long form of the policy can be viewed on the Administrative page. The short form is this: If your comment is not on topic and respectful to your fellow readers, I'm probably not going to run it.